Ergative languages make up a substantial percentage of the world’s languages. They have a case system which distinguishes the subject of a transitive verb from that of an intransitive, grouping the latter with the object — that is, the object of a transitive verb and the subject of an intransitive verb are in the same case, which we refer to as the nominative. However, ergative languages differ from one another in important ways. In Greenlandic Eskimo the nominative, whether it is (...) a subject or an object, is syntactically prominent in the clause, much like a subject in English; but in Warlpiri, the nominative is not prominent, more like an object. The variable prominence of the nominative manifests itself as well in the semantics, e.g., default scope of indefinite and quantified nominals. Using data from Greenlandic Eskimo and Warlpiri, and from Hindi, which represents a split ergative system, this paper develops a general theory of case which explains the observed differences amongst ergative languages. In addition, the theory is designed to account for the accusative language type, represented by English. (shrink)